Rapid Cycle Swing Adsorption for Compact Nitrogen Rejection
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Solution Overview
Problem
Conventional nitrogen rejection systems face challenges with large and expensive molecular sieve units, leading to increased operational and capital costs, particularly in floating facilities, due to stringent gas specifications and the need for additional treatment steps to reduce the load on initial gas treating processes.
Innovation Solution
A rapid cycle swing adsorption process utilizing adsorbent bed units that perform adsorption, depressurization, and purge steps to separate contaminants like CO2 and H2O from gaseous feed streams, with a purge stream used in a countercurrent direction to regenerate the adsorbent beds, reducing the size, weight, and capital expenses of the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional molecular sieve units are used for nitrogen rejection, then gas separation is achieved, but the system size, weight, and capital expenses increase significantly
Solution Approach 1:
The patent applies parameter changes by switching from conventional isobaric or isothermal swing adsorption to rapid cycle pressure and temperature swing adsorption (RCPTSA). This involves dynamically changing pressure and temperature parameters in a coordinated manner during the adsorption cycle, enabling faster cycling and reduced equipment size while maintaining separation effectiveness. The rapid cycling between high pressure/low temperature (adsorption) and low pressure/high temperature (desorption) states optimizes both performance and compactness.
2Reliability
If conventional molecular sieve units are used for nitrogen rejection, then gas separation is achieved, but capital expenses and operational costs increase
Solution Approach 1:
The patent merges pressure swing adsorption (PSA) and temperature swing adsorption (TSA) into a single integrated RCPTSA process. By combining these two separation mechanisms and coordinating their cycles, the system achieves enhanced separation performance with reduced equipment footprint and lower capital expenses compared to using separate PSA and TSA units.
Solution Approach 2:
The patent employs periodic action through rapid cycling between adsorption and desorption phases. The system alternates between filling the adsorbent bed at high pressure/low temperature and regenerating it at low pressure/high temperature, with cycle times optimized for maximum efficiency. This periodic operation enables continuous separation while minimizing equipment size and operational costs.
3Manufacturing precision
If additional treatment steps are added to reduce load on nitrogen rejection, then feed stream quality improves, but system size and complexity increase
Solution Approach 1:
The patent applies preliminary action by implementing feed stream pretreatment that removes heavy hydrocarbons and other contaminants before the gas enters the RCPTSA unit. This preliminary conditioning of the feed stream protects the adsorbent material, extends its life, and ensures optimal performance of the nitrogen rejection process, while the compact RCPTSA design minimizes the additional footprint required.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The process effectively dehydrates and removes CO2 to nitrogen rejection specifications in a compact system, reducing overall footprint, weight, and capital expenses compared to conventional molecular sieve configurations, while minimizing the use of solvents and emissions.
Implementation Method 1
passing a gaseous feed stream through an adsorbent bed unit having an adsorbent bed to separate one or more contaminants from the gaseous feed stream
Implementation Method 2
When the pressure is reduced, the adsorbed component is released, or desorbed from the adsorbent material
Implementation Method 3
the purge step comprises passing a purge stream into the adsorbent bed unit, wherein the purge stream is passed in a countercurrent direction relative to the direction of the feed stream
Data Source
AI summary
Provided are apparatus and systems for performing a swing adsorption process. This swing adsorption process may involve passing streams through adsorbent bed units to treat the feed stream to form a stream that complies with nitrogen rejection specifications. The process may involve using at least a portion of the nitrogen rejection process product streams as a purge for the swing adsorption process.